Re: Request/question from RMS

[Andrew Cagney <ac131313 at cygnus dot com>]

> Date: Thu, 10 Jan 2002 09:45:26 -0500
>> From: Andrew Cagney <ac131313@cygnus.com>
>> 
> 
>> > In Emacs .gdbinit I found this:
>> > 
>> > define xreload
>> > set $valmask = ((long)1 << gdb_valbits) - 1
>> > set $nonvalbits = gdb_emacs_intbits - gdb_valbits
>> > end
> 
> [...]
> 
>> > I think GDB should avoid making this necessary--that it should
>> > reread .gdbinit when it reloads the executable.  Or there should
>> > be a certain user-defined command that will be run after GDB
>> > reloads the executable.
> 
>> 
>> I know there are now things like posthook-run commands.  However, 
>> without knowing how EMACS uses the above (I've no desire to debug emacs, 
>> debugging mozilla was scary enough :-^) it is hard to suggest a replacement.
> 
> 
> Here's an example of how this is used:
> 
>     define xint
>     print (($ & $valmask) << $nonvalbits) >> $nonvalbits
>     end
>     document xint
>     Print $, assuming it is an Emacs Lisp integer.  This gets the sign right.
>     end
>     define xsymbol
>     print (struct Lisp_Symbol *) ((((int) $) & $valmask) | gdb_data_seg_bits)
>     output (char*)$->name->data
>     echo \n
>     end
>     document xsymbol
>     Print the name and address of the symbol $.
>     This command assumes that $ is an Emacs Lisp symbol value.
>     end


Ok.

This suggests that:

	define hookpost-run
	set $valmask = ((long)1 << gdb_valbits) - 1
	set $nonvalbits = gdb_emacs_intbits - gdb_valbits
	end

should do the trick.

	Andrew